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Men's Olympic swimming preview

Just like four years ago in Beijing, Michael Phelps will dominate the swimming news coming out of London. But this time he'll have a co-star in Ryan Lochte, who beat Phelps in the 400-meter individual medley at the U.S. trials on the way to qualifying for four solo events and at least one relay in the Olympics. The two raced each in four events in Omaha, Neb; Phelps won three of them, including the 100 butterfly, which Lochte had never contested before at the national level. The other three finals -- the 400 IM, the 200 freestyle and the 200 IM -- were breathtakingly close. Now that Phelps has dropped the 200 free, the two will face each other just twice in London. Both races promise to be thrillers.

[Sport Explainer: Swimming]

Phelps and Lochte will be the favorites, or co-favorites, in every race they swim. The toughest event on either athlete's program will be the 200 freestyle, which Phelps' coach, Bob Bowman, predicts will be "epic." Even though Phelps dropped the event to focus on the 400 freestyle relay, Lochte will have his hands full with an international field that will be the deepest of any in London. Contenders include France's Yannick Agnel, who has the best time in the world this year; world-record holder Paul Beidermann of Germany; and the always-dangerous Park Tae-hwan of South Korea.

In the 100 freestyle, the man to watch is 20-year-old world champion James Magnussen of Australia, the only person who has finished in under 48 seconds five times. To keep his mystique growing before the Games, Magnussen, a former rugby league player who turned to swimming after losing his under-16 grand final, has refused interviews with all but the Australian press. His competition includes Cesar Cielo, the world-record holder in the race. Cielo also has the world's best time in the 50 free. He'll be carrying the banner for Brazil as it prepares to take over the Olympic spotlight heading into 2016.

Japan's Kosuke Kitajima, a two-time Olympic champion in the 100 and 200 breaststrokes, could become the first man to win an Olympic event three times if he takes the 100 breaststroke on Day 2 -- that is, if Phelps doesn't beat him to it by claiming the 400 IM on Day 1.

China's Sun Yang, 20, will be favored to win the 400 free and could threaten the world record he set in the 1500 free at the World Championships in Shanghai last summer. Sun's time of 14.42.30, from April, is more than five seconds faster than Park's 14:47.38, the world's second-best time this year.

The U.S. is strong in every event that Phelps and/or Lochte swims. And its prospects for medals are solid in a few others, including the 100 backstroke (at trials, Matt Grevers won in a time of 52.08, best in the world this year and just .14 off Aaron Peirsol's 2009 world record); the 100 breaststroke (Brendan Hansen's trials time of 59.68 is fourth best in the world this year); and the 50 freestyle, as Cullen Jones and Anthony Ervin are both within a quarter second of Cielo's top time of 21.38.

The biggest concern for the Americans may be the 4x100 relay, an event in which they have never failed to medal when entered. Australia is the prohibitive favorite, but France, Russia and the USA will be in a tight battle for the other two medals. It's not inconceivable that the U.S. will use its best athletes in the relay pool in the morning prelims -- to secure a good lane -- as well as in the finals.

Michael Phelps vs. Ryan Lochte, 400 and 200 individual medleys: Hungary's Laszlo Cseh interrupted the Americans' match races in Beijing, beating Lochte to the silver medal in both events. Lochte seems far stronger and more focused this time around. But he will still have the 200 backstroke final shortly before the 200 IM. And he'll have plenty of challengers in the former event, including teammate Tyler Clary.

Ryan Lochte vs. Ryosuke Irie, 200 backstroke: Lochte is a former world-record holder and the reigning Olympic and world champion, but Japan's Irie has four of the top six times in the world this year, including the top mark of 1:54.02.

Michael Phelps vs. Serbia's Milorad Cavic, 100 butterfly: Since Phelps edged the Serb by one-hundredth of a second in the most thrilling individual-race finish in Beijing, Cavic lost the rematch, at the 2009 Worlds in Rome, and underwent back surgery to repair a herniated disk in 2010. Cavic's 51.45 from the European Championships is the third-best time in the world this year, but it's pretty far off Phelps' 51.14 from the U.S. trials. (Phelps' teammate Tyler McGill clocked a 51.32.) "I wouldn't be here if I didn't think I could win a medal," Cavic told The Associated Press. "What color that might be I don't know."

Brendan Hansen vs. Kosuke Kitajima, 100 breaststroke: Though the two were considered the top breaststrokers in the world for several years, Hansen has never beaten Kitajima in an Olympic race. Now that Hansen has made a successful comeback after a two-year retirement, he'll have one more chance, in the 100 breaststroke in London. When he saw his old nemesis, who now trains at USC, at the U.S. trials, Hansen gave him a hug. "I made it as awkward as I possibly could," said Hansen, adding that he was glad Kitajima saw him win the 100 breaststroke. "At the end of the day, when he gets on the blocks, he's got to know the only guy that has beaten him in the last 10 years is me."

Scott Weltz, who has trained alone with his former UC Davis coach, Pete Motekaitis, since that program was cut two years ago; who had never placed higher than fourth in a nationals meet; and who has no sponsors other than the people who have donated to an Internet fundraising site a friend set up, scored the biggest men's upset at the U.S. trials when he turned in a blazing final 50 of the 200 breaststroke to defeat runner-up Clark Burckle and the two overwhelming favorites, American record-holder Eric Shanteau and Hansen, the former world-record holder. In London, Weltz, 25, will face Kitajima and another Japanese swimmer, Ryo Tateishi, who has four of the top eight times in the world this year.

Phelps has four chances to become the first man to win an Olympic event three times (in the 400 and 200 individual medleys and the 200 and 100 butterflies); Kitajima has two (in the 100 and 200 breaststrokes). Several others have tried and failed to get that historic triple, including Russia's Alexander Popov (100 freestyle) and Australia's Kieren Perkins and Grant Hackett (both 1500 free).